1. Field of the Invention
The present invention relates in general to digital computing apparatus for preparing document text and, more particularly, for extracting format structure information and retrieving sentences from document data.
2. Description of the Background
Document processing systems as known in the art, e.g., word processors, are used for creating documents.
However, in cases where a user creates a document consisting of several pages, or a document having a large volume, e.g., a manual, it is difficult for the user to view the entire construction of the document while it is being created. As a result, disadvantageously, the user may unwittingly include the same document data in more than one location in the document, or delete document data i the belief it is included elsewhere in the document.
One prior art technique employed in an effort to overcome these difficulties consists of displaying the structure of the created document while it is being created. More specifically, a format structure of the document consisting of the document title, chapter titles and section titles to the extent created is displayed. FIG. 1 shows a screen display of a format structure embodying the prior art technique. As shown in FIG. 1, window 10 is generated to display the format information of the created document, while window 12 displays a portion of the created document. In FIG. 1, it is assumed that the user has only completed the document through section 2.1 and is now in the process of preparing section 2.2 of chapter 2. Accordingly, window 10 displays the title of the document, the titles of chapters 1 and 2, and the titles of section 2.1 and 2.2 of chapter 2 as format structure information. However, the displayed format structure information is inherently limited to showing only superficial characteristics of the created document and does not show the content of the created document itself. Therefore, even if the user studies the format structure information, he is still not provided with any detailed information regarding the content of the created document. As a result, the user must directly access and search the text of the created document in order to obtain detailed information about the document. Searching the text of the created document can be time consuming and frustrating for the user.
Also, during the creation of a document, the user may wish to refer back to one or more particular sentences in the portion of the document already created. To facilitate this effort, the user may designate a reference word and request retrieval of sentences including the reference word. However, in accordance with prior art document processing systems, every sentence including a word which coincides with the reference word is retrieved. Therefore, it is likely that sentences will be retrieved that include the reference word but that are not the particular sentence or sentences sought by the user. Therefore, prior art document processing systems do not enable a user to retrieve only sentences having a content of particular interest to the user.